Check valve with accelerated closure

ABSTRACT

A check valve including a valve body and a flapper assembly, the valve body defining an inlet, an outlet, an interior cavity, and a port in the interior cavity; the flapper assembly movable between an open position, providing fluid communication between the inlet and outlet, and a closed position, isolating the inlet from the outlet, the flapper assembly including a resilient body and a spring assembly, the spring assembly configured to bias the flap portion of the resilient body towards the closed position, the spring assembly including a spring and a backing plate mounted on opposite surfaces of the resilient body and configured to increase the stiffness of the intermediate portion of the resilient body.

TECHNICAL FIELD

Field of Use

The present invention relates generally to valves and, in particular, tocheck valves for regulating fluid flow.

Related Art

In a fluid system that transports a fluid from one location to another,it can be desirable to allow the fluid to flow in only one direction. Acheck valve, a type of valve that allows fluid flow in only onedirection, typically includes a disc that is configured to cover aninternal opening in the valve to close the valve and to move away fromthe internal opening to open the valve. When a pump positioned upstreamfrom a check valve in such a fluid system shuts down, any delay betweenwhen the pump stops pushing the fluid and when the check valve is fullyclosed can allow the fluid to flow in reverse. If the fluid beyond thevalve is allowed to flow in reverse, the disc can slam closed quickly,creating noise and vibration in the piping system and potentiallydamaging the disc and other fluid system components upstream from thecheck valve over long periods of use.

SUMMARY

It is to be understood that this summary is not an extensive overview ofthe disclosure. This summary is exemplary and not restrictive, and it isintended to neither identify key or critical elements of the disclosurenor delineate the scope thereof. The sole purpose of this summary is toexplain and exemplify certain concepts of the disclosure as anintroduction to the following complete and extensive detaileddescription.

In one aspect, disclosed is a check valve including a valve body and aflapper assembly, the valve body defining an inlet, an outlet, aninterior cavity, and a port in the interior cavity; the flapper assemblymovable between an open position, providing fluid communication betweenthe inlet and outlet, and a closed position, isolating the inlet fromthe outlet, the flapper assembly including a resilient body and a springassembly, the spring assembly configured to bias the flap portion of theresilient body towards the closed position, the spring assemblyincluding a spring and a backing plate mounted on opposite surfaces ofthe resilient body and configured to increase the stiffness of theintermediate portion of the resilient body.

In a further aspect, disclosed is a check valve, comprising: a valvebody defining an inlet, an outlet and an interior cavity, the valve bodyfurther defining a port in the interior cavity that has acircumferential downstream port shoulder surface; and a flapper assemblythat is movable between an open position, providing fluid communicationbetween the inlet and outlet, and a closed position, isolating the inletfrom the outlet. In one aspect, the flapper assembly comprises: aresilient body extending from a proximal hinge portion to anintermediate portion and to a distal flap portion, the hinge portionconfigured to be fixedly mounted in the valve body, wherein theintermediate portion and the flap portion have an upstream surface and adownstream surface; and wherein portions of an upstream surface of theflap portion are configured to seal the downstream port shoulder surfaceof the valve body when the flap portion is in the closed position. Inone aspect, the flapper assembly further comprises a spring assemblythat is configured to bias the flap portion of the resilient bodytowards the closed position, the spring assembly comprising: a springcomprising a proximal mounting end that is mounted to a portion of thedownstream surface of the intermediate portion of the resilient body anda distal end that is configured to slideably engage portions of thedownstream surface of the flap portion; and a backing plate that ismounted to a portion of the upstream surface of the intermediate portionof the resilient body in opposition to the proximal mounting end,wherein the proximate mounting end and the backing plate are configuredto increase the stiffness of the intermediate portion of the resilientbody relative to the proximal hinge portion and the distal flap portionof the resilient body.

In another aspect, the spring can define a spring step at a transitionfrom the proximal mounting end to the middle portion. In a furtheraspect, only the bottom portion of the distal end of the spring and aportion of the middle portion of the spring adjacent to the spring stepare in contact with the downstream surface of the resilient body

Various implementations described in the present disclosure may includeadditional systems, methods, features, and advantages, which may notnecessarily be expressly disclosed herein but will be apparent to one ofordinary skill in the art upon examination of the following detaileddescription and accompanying drawings. It is intended that all suchsystems, methods, features, and advantages be included within thepresent disclosure and protected by the accompanying claims. Thefeatures and advantages of such implementations may be realized andobtained by means of the systems, methods, features particularly pointedout in the appended claims. These and other features will become morefully apparent from the following description and appended claims, ormay be learned by the practice of such exemplary implementations as setforth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several aspects of the inventionand together with the description, serve to explain various principlesof the invention. Corresponding features and components throughout thefigures may be designated by matching reference characters for the sakeof consistency and clarity.

FIG. 1 is perspective cut-away view of a check valve comprising aflapper assembly in accordance with one aspect of the currentdisclosure.

FIG. 2 is a sectional view of the check valve of FIG. 1 taken along line2-2 of FIG. 1 in accordance with another aspect of the currentdisclosure wherein the flapper assembly includes a hinge pin.

FIG. 3 is a detail view of the check valve of FIG. 2 taken from detail 3of FIG. 2.

FIG. 4 is a perspective view of the flapper assembly of FIG. 2.

FIG. 5 is an exploded view of the flapper assembly of FIG. 2.

FIG. 6 is a sectional view of the flapper assembly of FIG. 2 taken alongline 6-6 of FIG. 4.

FIG. 7 is a detail view of the flapper assembly of FIG. 2 taken fromdetail 7 of FIG. 6.

FIG. 8 is a sectional view of a spring of a spring assembly of theflapper assembly of FIG. 2 taken from FIG. 6 wherein the spring is shownin a slightly flexed position of FIG. 6 and in a relaxed position.

FIG. 9 is a detail view of the spring of FIG. 8 taken from detail 9 ofFIG. 8.

FIG. 10 is a detail view of the spring of FIG. 8 taken from detail 10 ofFIG. 8.

DETAILED DESCRIPTION

The present invention can be understood more readily by reference to thefollowing detailed description, examples, drawings, and claims, andtheir previous and following description. However, before the presentdevices, systems, and/or methods are disclosed and described, it is tobe understood that this invention is not limited to the specificdevices, systems, and/or methods disclosed unless otherwise specified,as such can, of course, vary. It is also to be understood that theterminology used herein is for the purpose of describing particularaspects only and is not intended to be limiting.

The following description of the invention is provided as an enablingteaching of the invention in its best, currently known embodiment. Tothis end, those skilled in the relevant art will recognize andappreciate that many changes can be made to the one aspect of theinvention described herein, while still obtaining the beneficial resultsof the present invention. It will also be apparent that some of thedesired benefits of the present invention can be obtained by selectingsome of the features of the present invention without utilizing otherfeatures. Accordingly, those who work in the art will recognize thatmany modifications and adaptations to the present invention are possibleand can even be desirable in certain circumstances and are a part of thepresent invention. Thus, the following description is provided asillustrative of the principles of the present invention and not inlimitation thereof.

As used throughout, the singular forms “a,” “an” and “the” includeplural referents unless the context clearly dictates otherwise. Thus,for example, reference to “a sacrificial element” can include two ormore such sacrificial elements unless the context indicates otherwise.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect comprises from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

For purposes of the current disclosure, a material property or dimensionmeasuring about X or substantially X on a particular measurement scalemeasures within a range between X plus an industry-standard uppertolerance for the specified measurement and X minus an industry-standardlower tolerance for the specified measurement. Because tolerances canvary between different materials, processes and between differentmodels, the tolerance for a particular measurement of a particularcomponent can fall within a range of tolerances.

As used herein, the terms “optional” or “optionally” mean that thesubsequently described event or circumstance may or may not occur, andthat the description comprises instances where said event orcircumstance occurs and instances where it does not.

The word “or” as used herein means any one member of a particular listand also comprises any combination of members of that list.

In one aspect, a check valve and associated methods, systems, devices,and various apparatuses are described herein. The check valve cancomprise a flapper assembly comprising a spring. In one aspect, thecheck valve disclosed herein is, for example and without limitation, afull flow valve in which the flow area is equal to or greater than theequivalent pipe size throughout. In another aspect, the check valvedisclosed herein complies with the requirements ANSI/AWWA C508 includingthe 1,000,000 cycle-test requirement.

Various materials can be used to fabricate the various components of thecheck valve 100. The disclosure of the specific materials or finishes ortypes of materials or finishes listed, however, is not intended to belimiting on the current disclosure. One of ordinary skill in the artwould know to substitute equivalent materials where appropriate.

In one aspect, as shown in FIGS. 1 and 2, a check valve 100 comprises avalve body 110 and a flapper assembly 200, which can also be describedas a check valve disc assembly and defines a primary flow direction 101.The valve body 110 defines an inlet 170, an outlet 180, an outersurface, and an interior cavity 116 defining an inner surface 112. Theinner surface 112 can be coated with an epoxy film or other coating toprevent the fluid in the valve from contacting the material used to formthe valve body 110. As shown in FIG. 2, the valve body defines a port130 in the interior cavity 116 that has a circumferential downstreamport shoulder surface 131. An inside diameter D1 and an outside diameterD2 are shown defined by the port shoulder surface 131 of the port 130 ofthe valve body 110. The valve body 110 can comprise an inlet flangedefining mounting hole bores and an outlet flange defining mounting holebores. The check valve 100 can further comprise an access plug 105 sothat any fluid inside the check valve 100 can be drained out, so that anexternal backflow device can be installed to manually open the flapperassembly, or so that the interior cavity 116 can be otherwise accessed.

Optionally, the valve body 110 can comprise a valve cover 120 that isseparate from a main portion 115 of the valve body 110 and attached tothe main portion 115 with a plurality of fasteners. The valve cover 120comprises an outer surface, an inner surface, a boss, a boss cover, anda plurality of mounting fasteners. The valve cover 120 defines aplurality of mounting hole bores for mounting the boss cover with aplurality of boss cover fasteners. The boss cover may be replaced with amechanical position indicator (not shown) or other device and may beremoved to allow access to the interior of the check valve 100.Furthermore, the boss, boss cover, and boss cover fasteners may not bepresent on the valve cover 120.

Optionally, a gasket 127 is positioned between the main portion 115 andthe valve cover 120 and facilitates a tight seal between the mainportion 115 and the valve cover 120. The gasket 127 may define holes(not shown) to provide clearance for fasteners. The gasket 127 mayadditionally define holes that provide clearance for movement of partsof a valve position indicator (not shown), which in some installationsis mounted to the boss of the valve cover 120. The valve positionindicator indicates the position of the flapper assembly 200 of thecheck valve 100—whether the check valve 100 is open or closed orsomewhere in between. The gasket 127 can be made from a rubber such as,for example and without limitation, Buna-N rubber (i.e., nitrile),ethylene propylene diene (EPDM) rubber, or silicone.

Components of the check valve including the valve body 110, the accessplug 105, and the boss cover can be made from, for example and withoutlimitation, ductile iron or an equivalently suitable iron material. Thevalve body 110, boss cover, or the access plug 105 can also be made fromanother material or a combination of other materials including copper,bronze, steel, plastic (including fiber-reinforced plastic), or anequivalently suitable material.

Optionally, the valve body 110 further comprises a recess 125 positionedproximate to a portion of the port shoulder surface 131 in which thehinge portion 220 of the resilient body 210 is configured to be fixedlymounted. As shown in FIGS. 1 and 2, the valve body 110 extends along alongitudinal axis 109 of the valve body 110 between the inlet 170 andthe outlet 180. The port shoulder surface 131 can be angled with respectto the longitudinal axis 109 by an angle 117 measuring between 0 and 180degrees. For example and without limitation, the angle 117 can be about45 degrees. Where the port shoulder surface 131 is angled with respectto the longitudinal axis 109 by the angle 117, the recess 125 can bepositioned upstream from the port shoulder surface 131.

The flapper assembly 200 is shown in solid lines in FIG. 2 in an openposition B and is shown in broken lines in FIG. 2 in a closed positionA. The flapper assembly 200 comprises a resilient body 210, which canalso be described as a disc flapper or a flapper disc, and a springassembly 300. The resilient body 210 can be a monolithic body includinga proximal hinge portion 220, an intermediate portion 230, and a distalflap portion 240. The resilient body 210 extends from the proximal hingeportion 220 to the intermediate portion 230 to the distal flap portion240. The hinge portion 220 is configured to be fixedly mounted in thevalve body 110. The intermediate portion 230 and the flap portion 240together define an upstream surface 211 and a downstream surface 212.The intermediate portion 230 defines an upstream surface 231 and adownstream surface 232 and the flap portion 240 defines an upstreamsurface 241 and a downstream surface 242. The upstream surface 211 caninclude the upstream surfaces 231 and 241 and the downstream surface 212can include the downstream surfaces 232 and 242. As shown, the flapportion 240 can be, for example and without limitation, disc-shaped(i.e., substantially round or circular in shape and having a thickness).The flap portion 240 as well as the resilient body 210 overall can befabricated from a polymeric material such as, for example and withoutlimitation, Buna-N (i.e., nitrile), ethylene propylene diene (EPDM)rubber, and other resilient materials. The process used to form theresilient body 210 can be a molding process such as, for example andwithout limitation, an injection molding process.

Optionally, the flapper assembly 200 includes a hinge pin 205 and astiffening insert 250 wrapped with a reinforcement strap 260 andencapsulated within the resilient body 210. The hinge pin 205 can helpthe hinge portion 220 of the resilient body 210 keep its shape whensandwiched between the valve body 110 and the cover 130, while thestiffening insert 250 can help keep the flap portion 240 flat underpressure. The reinforcement strap 260 couples the stiffening insert 250to the hinge pin 205 and wraps at least partially around the stiffeninginsert 250 and the hinge pin 205. As shown in FIG. 1, however, theflapper assembly 200 may not include the hinge pin 205, the stiffeninginsert 250, or the reinforcement strap 260. The stiffening insert 250and the hinge pin 205 can be made from a steel such as, for example andwithout limitation, hot-rolled steel. The stiffening insert 250 or thehinge pin 205 can also be made from another metal, a polymer, or anyrigid material or from a combination of two or more of these materials.For example and without limitation, the reinforcement strap 260 can bemade from a cloth such as fiberglass cloth or from a nylon material orother flexible material having similar mechanical properties. Thereinforcement strap 260 can also be made from another material orcombination of materials with a tensile strength and other propertiesresulting in the reinforcement strap 260 being able to prevent resilientbody 210 from stretching or deforming over time.

The spring assembly 300 comprises a spring 400 including a proximalmounting end 410 and a distal end 430. As shown in FIGS. 3 and 4, theproximal mounting end 410 of the spring 400 is mounted to a portion ofthe downstream surface 232 of the intermediate portion 230 of theresilient body 210. As shown in FIG. 8, the proximal mounting end 410 ofthe spring 400 is substantially planar when the spring 400 is in arelaxed position or in a slightly flexed position. The distal end isconfigured to slideably engage portions of the downstream surface 242 ofthe flap portion 240. The spring 400 further comprises a middle portion420—that can be planar in various aspects—that extends from the proximalmounting end 410 to the distal end 430. Optionally, the spring 400defines a spring step 415 at a transition from the proximal mounting end410 to the middle portion 420. As shown, the spring 400 is disposedentirely within the interior cavity 116 of the valve body 110 and doesnot contact the recess 125. In one aspect, a terminal edge 412 of theproximal mounting end 410 of the spring 400 is offset from the interiorsurface 112 of the valve body 110 by a distance approximately equal toan offset distance 417.

In one aspect, the spring assembly 300 also comprises a backing plate500. As shown in FIG. 5, the backing plate 500 is substantially planar,although the backing plate 500 can also be of another shape. The backingplate 500 can be a single plate or can comprise a plurality of separateplates that differ in size and proportions from that shown. The backingplate 500 can define any straight-sided or rounded shape such as, forexample and without limitation, a rectangle or a circle, that ismountable to the intermediate portion 230 of the resilient body 210. Thebacking plate 500 can, for example and without limitation, comprisewashers. Optionally, a length and a width of the backing plate aredimensionally similar to a length and a width of the proximal mountingend 410 of the spring 400. By being dimensionally similar, the lengthand the width dimensions of the backing plate 500 are about equal to thelength and width dimensions of the proximal mounting end 410 of thespring 400. As shown, the backing plate 500 can be mounted to a portionof the upstream surface 231 of the intermediate portion 230 of theresilient body 210 opposite the proximal mounting end 410 of the spring400, wherein the proximate mounting end 410 and the backing plate 500are configured to selectively increase the stiffness of the intermediateportion 230 of the resilient body 210 relative to the proximal hingeportion 220 and the distal flap portion 240 of the resilient body 210.

In one aspect, the check valve 100 further comprises a plurality offasteners 390, wherein the intermediate portion 230 of the resilientbody 210, the proximal mounting end 410 of the spring 400, and thebacking plate 500 each define a plurality of openings, and wherein therespective openings in the intermediate portion 230 of the resilientbody 210, the proximal mounting end 410, and the backing plate 500 arecoaxially aligned and are configured to operatively receive theplurality of fasteners 390 to fixedly mount the proximal mounting end410 of the spring 400 and the backing plate 500 to the intermediateportion 230 of the resilient body 210. As shown in FIG. 1, a total ofthree fasteners 390 may be used in the flapper assembly 200. As shown inFIG. 4, a total of four fasteners 390 may be used in the flapperassembly 200. The number of fasteners 390 may be as few as zero—ifanother fastening method is used—or may be greater than four.

FIGS. 3 through 6 additionally disclose the flapper assembly 200.Optionally, the flapper assembly 200 comprises a stopper 208 that can beformed in the resilient body 210. The resilient body 210 is showncomprising the hinge portion 220, the intermediate portion 230, and theflap portion 240. As shown, the hinge portion 220 comprises the hingepin 205. The hinge portion 220 of the flapper assembly 200, however,need not rotate about the hinge pin 205 to be considered a hingeportion. In addition, neither the hinge portion 220 nor the hinge pin205 need to rotate with respect to the valve body 110 during operation.The hinge portion 220 of the flapper assembly 200 can be shaped so as tofill and remain stationary inside the recess 125 of the valve body 110.

FIGS. 6 and 7 show the flapper assembly 200. As shown in FIG. 6, theintermediate portion 230 of the resilient body 210 has a firstcross-sectional thickness 215, and the flap portion 240 of the resilientbody 210 has a second cross-sectional thickness 216 that is greater thanthe first cross-sectional thickness 215. The intermediate portion 230and the flap portion 240 of the resilient body 210, however, can alsohave the same cross-section thickness. As shown in FIG. 7, the springstep 415 can be formed to substantially overlie a first step 213 that isformed in the downstream surface 212 of the resilient body 210 at atransition from the intermediate portion 230 to the flap portion 240.Optionally, the upstream surface 211 of the resilient body 210 candefine a second step 214 at a transition from the intermediate portion230 to the flap portion 240.

Optionally, as shown in FIG. 6, the resilient body 210 of the flapperassembly 200 comprises a sealing portion 510, which can be an O-ring inone aspect. As shown, the sealing portion 510 is formed as part of theresilient body 210 to ensure a tight seal between the resilient body 210and the port shoulder surface 131. The sealing portion 510 has adiameter D4 measuring a value between the values of the diameter D1 andthe diameter D2 of the port shoulder surface 131.

FIGS. 8-10 disclose additional features of the spring 400. As shown inFIG. 8, the spring 400 defines an mount offset distance 802 and apresprung distance 803. The mount offset distance 802 is the distancebetween a mounting surface of the proximal mounting end 410 and a bottomportion 435 of the distal end 430. The presprung distance 803 is thedistance between the bottom portion 435 when the spring 400 is in arelaxed state shown in solid lines and the bottom portion 435 when thespring 400 is in a presprung state shown in broken lines (i.e., asinstalled in the flapper assembly 200 when the flapper assembly 200 isin the closed position A inside the check valve 100). As shown, thepresprung distance 803 is approximately equal to a diameter (i.e., twicea radius 1001 shown in FIG. 10) of a curved cross-sectional shape at thedistal end 430 of the spring 400. As shown in FIG. 9, the spring step415 defines a spring thickness T measuring approximately 0.020 inches(0.5 millimeters), a step angle 901 measuring approximately 30 degreesand a step distance 902 approximately equal to a height of the firststep 213 of the resilient body 210. Optionally, the step angle 901 canmeasure more or less than 30 degrees, and the spring thickness T canmeasure more or less than 0.020 inches.

In one aspect, as shown in FIG. 10, the distal end 430 of the spring 400comprises a curved cross-sectional shape with the bottom portion 435having the outside radius 1001 and defining a clearance gap 1002 betweenan upstream surface 421 of the middle portion 420 of the spring 400 anda terminal end 437 of the spring 400. The bottom portion 435 of thedistal end 430 is configured to slideably engage portions of thedownstream surface 232 of the flap portion 240 and to space at least aportion of the middle portion 420 of the spring 400 away from thedownstream surface 232 of the flap portion 240. Additionally, the curvedcross-sectional shape—which can also be described as a loop in thespring 400 at the distal end 430—allows smooth slideable engagement ofthe distal end 430 of the spring 400 with the downstream surface 232 ofthe flap portion 240. Optionally, the spring 400 can be shaped so thatonly the bottom portion 435 of the distal end 430 of the spring 400 anda portion of the middle portion 420 of the spring 400 adjacent to thespring step 415 are in contact with the downstream surface 212 of theresilient body 210. In another aspect, it is contemplated that thespring can be shaped to contact the flap portion 240 along the entirelength of the flap portion 240.

A material such as used to form the spring 400 or the resilient body 210exhibits a variety of mechanical properties including a modulus ofelasticity or Young's modulus. As shown, the spring 400 is made from anon-elastomeric material and the resilient body 210 is made from anelastomeric material, where an elastomeric material is a material havinga relatively low Young's modulus that is generally adapted to expand,contract, compress, or stretch under normal operating conditions to adegree that is visible by the naked eye. An elastomeric material such asrubber has a Young's modulus of 15,000 psi (approximately 0.1 GPa),which is about three orders of magnitude below the Young's modulus ofone of the weaker materials used for springs such as phosphor bronze.The spring 400 can be formed from a material having a modulus ofelasticity in tension equal to that of phosphor bronze or at least about15,000,000 psi (approximately 103 GPa). More specifically, the spring400 can be formed from a material having a modulus of elasticity intension of about 28,000,000 psi (approximately 193 GPa). Optionally, thespring 400 can be formed from an AISI 301 series cold-drawn stainlesssteel meeting the requirements of ASTM A666 or the equivalentspecification (e.g., UNS S30100, SAE J230, and QQ-S-766). As shown, thespring 400 is formed from a material having a modulus of elasticity thatis greater than the modulus of elasticity of the material that forms theresilient body 210.

The spring 300 and the backing plate 500 can be formed from a flat blankof raw material using one or more material removal processes such as,for example and without limitation, machining, stamping, punching,laser-cutting, abrasive-water-jet-cutting, and chemical milling oretching, optionally in combination with forming processes such as, forexample and without limitation, casting, forging, stamping, bending, andthree-dimensional printing.

The flapper assembly 200 can be installed in a check valve ofpotentially any size from a check valve having a 2″ inside diameter to acheck valve having a 24″ inside diameter. The check valve utilizing theflapper assembly 200, however, can optionally be outside of this range(i.e., the check valve can have an inside diameter smaller than 2″ orgreater than 24″).

The spring assembly 300 is configured to bias the flap portion 240 ofthe resilient body 210 towards the closed position A. When the spring400 is pre-sprung to a presprung distance 803, the spring assembly 300is able to apply a force to the flap portion 240 of the resilient body210 even when the flapper assembly 200 is in the closed position A tofacilitate a positive seal against the downstream port surface 131. Inother words, the presprung distance 803 gives initial stiffness ormemory to the spring 300 when installed on the flapper assembly 200. Thelength and width, thickness, or material specification of the spring 400and various other characteristics of the spring assembly 300 and theflapper assembly 200 including the quantity of the springs 400 assembledto a single flapper assembly 200 can be adjusted to increase or decreasethe stiffness of the flapper assembly 200 and thus increase or decreasethe speed at which the flapper assembly 200 closes inside the checkvalve 100.

For example and without limitation, each of the fasteners 390 can betightened until the spring 400 and the backing plate 500 arerespectively snug (i.e., held flush) against the upstream surface 231and the downstream surface 232 of the intermediate portion 230 of theresilient body 210. Optionally, each of the fasteners 390 can beadditionally tightened past this point by one turn or 360 degrees. Noneof the fasteners 390, however, are tightened so much that the proximalmounting end 410 or the backing plate 500 is damaged. Optionally, thefastening torque used to install the fasteners 390 can be adjusted toincrease or decrease the stiffness of the flapper assembly 200 and thusthe speed at which the flapper assembly 200 closes inside the checkvalve 100.

The flapper assembly 200 is selectively movable about and between theopen position B, providing fluid communication between the inlet 170 andthe outlet 180, and the closed position A, isolating the inlet 170 fromthe outlet 180. The flapper assembly 200, however, can be made to stopat any point between the closed position A and the open position B byincorporating, for example and without limitation, a mechanical stopsuch as an external backflow device (not shown) installed through thevalve body 110, or simply by variation of the pressure of the fluidinside the valve. For purposes of describing the present disclosure, thecheck valve 100 is in the closed position A when the flapper assembly200 is in contact with the port shoulder surface 131. In contrast, thecheck valve 100 is in an open position when the flapper assembly 200 isnot in contact with the port shoulder surface 131. When the flapperassembly 200 is in contact with the inner surface 112 of the valve body110, it can be said that the flapper assembly 200 is fully open. Thisfully open check valve position is shown in FIG. 2 as the open positionB.

When the flapper assembly 200 is fully open, the proximal mounting end410 of the spring 400 is made to flex together with the intermediateportion 230 of the resilient body 210. As shown in FIGS. 2 and 3, theintermediate portion 230 of the flapper assembly 200 defines a radius R1between the fastener 390 and the recess 125 and a radius R2 between thefastener 390 and the flap portion 230. The radius R2 may measure greaterthan the radius R1. The radius R2 may measure several times the radiusR1.

Upstream portions of the upstream surface 231 of the flap portion 240are configured to selectively seal the downstream port shoulder surface131 of the valve body 110 when the flap portion 240 is in the closedposition A. For example, the inlet surface 212 may form a substantiallyfluid-tight seal with the disc sealing surface 184 of the check valve100 when the flap portion 240 is in the closed position A.

The reinforcement strap 260 can increase the long-term strength or lifeof the flapper assembly 200. The life of the flapper assembly 200 can beincreased, especially on larger check valves, by using the reinforcementstrap 260 to carry at least some of the mechanical loads experienced bythe resilient body 210 during repeated open and close cycles.

In one aspect, a method of manufacturing the flapper assembly 200comprises drilling holes in the intermediate portion of the resilientbody 210 to receive the fasteners 390, positioning the proximal mountingend 410 and the backing plate 500 on opposite surfaces of the flapperassembly 200, and securing the spring assembly 300 to the resilient body210 with the fasteners 390. This method of manufacturing the flapperassembly 200 can be used to retrofit a flapper assembly not originallycontaining certain features disclosed herein.

In one aspect, a method of using the check valve 100 comprises openingthe flapper assembly 200 with the pressure of a fluid traveling withinthe check valve 100 and then closing the flapper assembly 200 with theaid of the spring assembly 300 disclosed herein. The method of using thecheck valve 100 can further comprise closing the flapper assembly 200before reverse flow is established inside the check valve 100 sufficientto cause water hammer.

One should note that conditional language, such as, among others, “can,”“could,” “might,” or “may,” unless specifically stated otherwise, orotherwise understood within the context as used, is generally intendedto convey that certain embodiments include, while other embodiments donot include, certain features, elements and/or steps. Thus, suchconditional language is not generally intended to imply that features,elements and/or steps are in any way required for one or more particularembodiments or that one or more particular embodiments necessarilyinclude logic for deciding, with or without user input or prompting,whether these features, elements and/or steps are included or are to beperformed in any particular embodiment.

It should be emphasized that the above-described embodiments are merelypossible examples of implementations, merely set forth for a clearunderstanding of the principles of the present disclosure. Any processdescriptions or blocks in flow diagrams should be understood asrepresenting modules, segments, or portions of code which include one ormore executable instructions for implementing specific logical functionsor steps in the process, and alternate implementations are included inwhich functions may not be included or executed at all, may be executedout of order from that shown or discussed, including substantiallyconcurrently or in reverse order, depending on the functionalityinvolved, as would be understood by those reasonably skilled in the artof the present disclosure. Many variations and modifications may be madeto the above-described embodiment(s) without departing substantiallyfrom the spirit and principles of the present disclosure. Further, thescope of the present disclosure is intended to cover any and allcombinations and sub-combinations of all elements, features, and aspectsdiscussed above. All such modifications and variations are intended tobe included herein within the scope of the present disclosure, and allpossible claims to individual aspects or combinations of elements orsteps are intended to be supported by the present disclosure.

1. A check valve, comprising: a valve body defining an inlet, an outletand an interior cavity, the valve body further defining a port in theinterior cavity that has a circumferential downstream port shouldersurface; and a flapper assembly that is movable between an openposition, providing fluid communication between the inlet and outlet,and a closed position, isolating the inlet from the outlet, the flapperassembly comprising: a resilient body extending from a proximal hingeportion to an intermediate portion and to a distal flap portion, whereinthe hinge portion is configured to be fixedly mounted in the valve body,wherein the intermediate portion and the flap portion have an upstreamsurface and a downstream surface, the downstream surface of theresilient body defining a first step at a transition from theintermediate portion to the flap portion; and wherein portions of anupstream surface of the flap portion are configured to seal thedownstream port shoulder surface of the valve body when the flap portionis in the closed position; and a spring assembly that is configured tobias the flap portion of the resilient body towards the closed position,the spring assembly comprising: a spring comprising a proximal mountingend that is mounted to a portion of the downstream surface of theintermediate portion of the resilient body, a distal end that isconfigured to slideably engage portions of the downstream surface of theflap portion, and a middle portion that extends from the proximalmounting end to the distal end; and a backing plate that is mounted to aportion of the upstream surface of the intermediate portion of theresilient body in opposition to the proximal mounting end, wherein theproximate mounting end and the backing plate are configured to increasethe stiffness of the intermediate portion of the resilient body relativeto the proximal hinge portion and the distal flap portion of theresilient body.
 2. The check valve of claim 1, wherein the valve bodyfurther comprises a recess positioned proximate a portion of the portshoulder surface, and wherein the hinge portion of the resilient body isconfigured to be fixedly mounted in the recess of the valve body.
 3. Thecheck valve of claim 1, wherein the valve body extends along alongitudinal axis of the valve body between the inlet and the outlet andwherein the port shoulder surface is angled with respect to thelongitudinal axis.
 4. The check valve of claim 1, wherein the backingplate and the proximal mounting end of the spring are substantiallyplanar.
 5. The check valve of claim 1, further comprising a plurality offasteners, wherein the intermediate portion of the resilient body, theproximal mounting end of the spring and the backing plate each define aplurality of openings, and wherein the respective openings in theintermediate portion of the resilient body, the proximal mounting end ofthe spring, and the backing plate are coaxially aligned and areconfigured to operatively receive the plurality of fasteners to fixedlymount the proximal mounting end of the spring and the backing plate tothe intermediate portion of the resilient body.
 6. The check valve ofclaim 1, wherein the middle portion is substantially planar.
 7. Thecheck valve of claim 6, wherein only the bottom portion of the distalend of the spring and a portion of the middle portion of the springadjacent to a spring step of the spring are in contact with thedownstream surface of the flap portion of the resilient body. 8.(canceled)
 9. The check valve of claim 1, wherein the upstream surfaceof the resilient body defines a second step at a transition from theintermediate portion to the flap portion.
 10. The check valve of claim1, wherein the spring defines a spring step at a transition from theproximal mounting end to the middle portion and wherein the spring stepsubstantially overlies the first step formed in the downstream surfaceof the resilient body.
 11. The check valve of claim 1, wherein thedistal end of the spring comprises a curved cross sectional shape inwhich a bottom portion of the curved cross-sectional shape is configuredto slideably engage portions of the downstream surface of the flapportion and to space the majority of the middle portion of the springaway from the downstream surface of the flap portion.
 12. The checkvalve of claim 1, wherein the flap portion is disc-shaped.
 13. A checkvalve, comprising: a valve body defining an inlet and an outlet, thevalve body further defining a port between the inlet and outlet that hasa circumferential downstream port shoulder surface and a recesspositioned proximate a portion of the port shoulder surface; and aflapper assembly that is movable between an open position, providingfluid communication between the inlet and outlet, and a closed position,isolating the inlet from the outlet, the flapper assembly comprising: aresilient body extending from a proximal hinge portion to anintermediate portion and to a distal flap portion, wherein the hingeportion is configured to be fixedly mounted in the recess of the valvebody, wherein the intermediate portion and the flap portion have anupstream surface and a downstream surface; and wherein upstream portionsof the flap portion are configured to seal the downstream port shouldersurface of the valve body when the flap portion is in the closedposition; and a spring assembly that is configured to bias the flapportion of the resilient body towards the closed position, the springassembly comprising; a spring comprising a proximal mounting end that ismounted to a portion of the downstream surface of the intermediateportion of the resilient body, a distal end having a curved crosssectional shape is which a bottom portion of the curved cross-sectionalshape is configured to slideably engage portions of the downstreamsurface of the flap portion, and a middle portion that extends from theproximal mounting end to the distal end, wherein the spring defines aspring step at a transition from the proximal mounting end to the middleportion, and wherein only the bottom portion of the distal end of thespring and a portion of the middle portion of the spring adjacent to thespring step are in contact with the downstream surface of the flapportion of the resilient body; and a backing plate that is mounted to aportion of the upstream surface of the intermediate portion of theresilient body in opposition to the proximal mounting end, wherein theproximate mounting end and the backing plate are configured to increasethe stiffness of the intermediate portion of the resilient body relativeto the proximal hinge portion and the distal flap portion of theresilient body.
 14. The check valve of claim 13, wherein the portshoulder surface is angled with respect to a longitudinal axis of thevalve body.
 15. The check valve of claim 13, wherein the proximalmounting end is substantially planar.
 16. The check valve of claim 15,wherein the backing plate is substantially planar and wherein thebacking plate is dimensionally similar to the proximal mounting end ofthe resilient body.
 17. The check valve of claim 13, further comprisinga plurality of fasteners, wherein the intermediate portion of theresilient body, the proximal mounting end and the backing plate eachdefine a plurality of openings, and wherein the respective openings inthe intermediate portion of the resilient body, the proximal mountingend and the backing plate are coaxially aligned and are configured tooperatively receive the plurality of fasteners to fixedly mount theproximal mounting end of the spring and the backing plate to theintermediate portion of the resilient body, and wherein the downstreamsurface of the resilient body defines a first step at a transition fromthe intermediate portion to the flap portion.
 18. The check valve ofclaim 17, wherein the upstream surface of the resilient body defines asecond step at a transition from the intermediate portion to the flapportion.
 19. The check valve of claim 17, wherein the spring stepsubstantially overlies the first step formed in the downstream surfaceof the resilient body.
 20. A flapper assembly for a check valve, thecheck valve having an inlet, an outlet and an interior cavity, the valvebody further defining a port in the interior cavity that has acircumferential downstream port shoulder surface, the flapper assemblycomprising: a resilient body extending from a proximal hinge portion toan intermediate portion and to a distal flap portion, wherein the hingeportion is configured to be fixedly mounted in the interior cavity ofthe valve body, wherein the intermediate portion and the flap portionhave an upstream surface and a downstream surface; and wherein upstreamportions of the flap portion are configured to seal the downstream portshoulder surface of the valve body when the flap portion is in a closedposition, isolating the inlet from the outlet; and a spring assemblythat is configured to bias the flap portion of the resilient bodytowards the closed position, the spring assembly comprising; a springcomprising a proximal mounting end that is mounted to a portion of thedownstream surface of the intermediate portion of the resilient body, adistal end having a curved cross sectional shape in which a bottomportion of the curved cross-sectional shape is configured to slideablyengage portions of the downstream surface of the flap portion, and amiddle portion that extends from the proximal mounting end to the distalend, wherein the spring defines a spring step at a transition from theproximal mounting end to the middle portion, and wherein only the bottomportion of the distal end of the spring and a portion of the middleportion of the spring adjacent to the spring step are in contact withthe downstream surface of the flap portion of the resilient body; and abacking plate that is mounted to a portion of the upstream surface ofthe intermediate portion of the resilient body in opposition to theproximal mounting end, wherein the proximate mounting end and thebacking plate are configured to increase the stiffness of theintermediate portion of the resilient body relative to the proximalhinge portion and the distal flap portion of the resilient body.
 21. Thecheck valve of claim 20, wherein the flap portion is disc-shaped.